Animal litter box

ABSTRACT

An animal litter box includes an evacuation container and a hood, the hood having a fixed hood, a movable hood, and a pair of connecting portions. The movable hood is configured to be moved rotatably either outside or inside the fixed hood such that an end edge of the movable hood is proximal to the fixed hood while maintaining a prescribed distance at least one of the fixed hood  31  and the movable hood is provided with a convex restricting portion which prevents a distance between an end edge on at least the one end of the movable hood  32  and the fixed hood  31  from being less than the prescribed distance.

CROSS-REFERENCE TO RELATED APPLICATION

This application is based on and claims the benefit of priority from Japanese Patent Application No. 2007-173554, filed on 29 Jun. 2007, the content of which is incorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates to an animal litter box.

BACKGROUND OF THE INVENTION

Conventionally, as a litter box for animals such as cats, a litter box has been known which is provided with an evacuation container of which upper surface is open and a hood covering an upper side of the evacuation container, the hood having an opening for an animal going in and out. For such an animal litter box with a hood, when cleaning up the box, it is necessary to remove the hood or put one's hand into the box from the opening formed on the hood. However, it takes much effort to take off the hood whenever cleaning up the box. Furthermore, it is hard to remove the urine or feces of the animal completely when putting one's hand into the box from the opening.

To solve the abovementioned problems, Japanese Unexamined Patent Application First Publication No. 2002-325520 (“the '520 application”) has disclosed an animal litter box comprising a hood having a fixed hood covering one half of an evacuation container, and a movable hood covering the other half of the evacuation container. The movable hood is formed to move rotatably, and the animal litter box is configured to store the movable hood inside or outside of the fixed hood when the movable hood is moved rotatably.

Regarding the animal litter box as described in the '520 application, a prescribed distance needs to be formed between the movable hood and the fixed hood so that the movable hood can be moved along the inner side or outer side the fixed hood. Here, in the case where the distance between the movable hood and the fixed hood is reduced, when the movable hood is opened or closed, the fixed hood may be contacted with the movable hood and the like due to small flexure or deformation of the fixed hood or the movable hood, which causes the movable hood to be stuck. On the other hand, in a case where the distance between the movable hood and the fixed hood is enlarged, the animal litter box cannot be sealed completely even though the movable hood is closed.

SUMMARY OF THE INVENTION

The present invention provides an animal litter box of which a movable hood can be opened and closed smoothly even though a distance between the movable hood and a fixed hood is small.

A convex restricting portion is provided which prevents the distance between the movable hood and the fixed hood from being less than a prescribed distance on the fixed hood and/or the movable hood, thereby accomplishing the present invention. More specifically, the present invention provides the following.

According to a first aspect of the invention, an animal litter box is provided which comprises an evacuation container of which an upper surface has an opening and a hood disposed above the evacuation container so as to cover the opening, the hood having a fixed hood disposed on one end of the evacuation container, a movable hood disposed on the other end of the evacuation container, and a pair of connecting portions which connect the movable hood to the fixed hood to be moved rotatably. The movable hood is configured to be moved rotatably outside or inside of the fixed hood in the state that an end edge on at least the one end of the movable hood is proximal to the fixed hood with maintaining a prescribed distance, and wherein at least one of the fixed hood and the movable hood is provided with a convex restricting portion which prevents a distance between an end edge on at least the one end of the movable hood and the fixed hood from being less than the prescribed distance.

According to a second aspect of the present invention, in an animal litter box according to the first aspect, when the movable hood is in a closed state, the movable hood has an overlapping portion with the fixed hood, and the pair of connecting portions is disposed in the vicinity of an end edge of the evacuation container in the overlapping portion so as to face each other, and connects the movable hood with the fixed hood.

According to a third aspect of the present invention, an animal litter box according to the first aspect or the second aspect has a movable hood that is configured to be moved rotatably outside the fixed hood, and the restricting part is composed of an inwardly protruding portion which is formed on an inner surface of an end edge on at least the one end on an upper surface of the movable hood. On an outer upper surface of the fixed hood, extending from the other end to the one end, a concave guiding groove for guiding the moving of the protruding portion when the movable hood is altered from a closed state to an open state is provided.

According to a fourth aspect of the present invention, an animal litter box according to the first aspect or the second aspect has a restricting portion that is composed of one or more inwardly protruding portions which are formed on an inner surface of an end edge on at least the one end of the movable hood.

According to a fifth aspect of the present invention, an animal litter box according to the first aspect or the second aspect has a restricting portion that is composed of a convexity which is formed on an outer upper surface of the fixed hood and which extends from the other end to the one end. A guiding member with a concavity which is hollow upward corresponding to a convex shape of the convexity is provided on an inner surface of an end edge on at least one end of an upper surface of the movable hood.

According to the animal litter box of the present invention, a movable hood can be opened and closed smoothly even though a distance between the movable hood and a fixed hood is reduced over prior art litter boxes.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will become more readily apparent from the Detailed Description of the Invention which proceeds with reference to the drawings, in which:

FIG. 1 is a perspective diagram of an animal litter box of the first embodiment of the present invention, which is viewed from a front side with a movable hood being in the closed state;

FIG. 2 is a perspective diagram of the animal litter box shown in FIG. 1, which is viewed from a rear side;

FIG. 3 is a side view of the animal litter box shown in FIG. 1;

FIG. 4 is a cross-sectional view taken along the line X-X in FIG. 3;

FIG. 5 is a partially enlarged view of a portion of FIG. 4;

FIG. 6 is a vertical sectional view in an anteroposterior direction of the animal litter box of the first embodiment with the movable hood being in a closed state;

FIG. 7 is a vertical sectional view in the anteroposterior direction of the animal litter box of the first embodiment with the movable hood being in an open state;

FIG. 8 is a sectional view of an animal litter box of a second embodiment of the present invention, which corresponds to that in FIG. 4; and

FIG. 9 is a sectional view of an animal litter box of a third embodiment of the present invention, which corresponds to that in FIG. 4.

DETAILED DESCRIPTION OF THE INVENTION

In the following, an animal litter box of the present invention is described with reference to the drawings, based on a first embodiment, which is a preferred embodiment.

As shown in FIG. 1, the animal litter box 1 of the first embodiment is provided with an evacuation container 2 of which an upper surface has an opening and a hood 3 disposed on an upper side of the evacuation container 2 so as to cover the opening. The evacuation container 2 is configured to include a bottom part of which shape of the surface is rectangular and sidewalls with a prescribed height which stand in a nearly vertical direction at each four sides which are the rims of the bottom part. The evacuation container 2 is a place where an animal using the animal litter box 1 of the present invention evacuates feces or urine, and granular materials called animal litter (not shown) can be dispersed as appropriate in the evacuation container 2.

The bottom part of the evacuation container 2 is configured to have a liquid permeable capability. In the first embodiment, as shown in FIG. 1, the bottom part has a plurality of rectangular liquid permeable openings, which makes the bottom part gridironed. The shape of the liquid permeable openings is not limited to be rectangular, and may be round, triangle, and the like. In addition, the size of the liquid permeable openings is preferably less than the size of granular materials so that the granular materials dispersed on the bottom part are prevented from dropping downward through the liquid permeable openings. A lower container 4 is disposed under the evacuation container 2. A drawer tray 41 which can be taken out in a horizontal direction is provided in the lower container 4, the drawer tray 41 which can collect liquid such as animal urine going through the bottom part of the evacuation container 2. An upper surface of the drawer tray 41 is open and a bottom part thereof is formed as a nearly rectangular shape. In addition, the bottom part of the drawer tray 41 is configured to be larger than the bottom part of the evacuation container 2. Furthermore, the bottom part of the drawer tray 41 can hold detachably and replaceably an absorbent sheet (not shown) which absorbs liquid such as animal urine going through the bottom part of the evacuation container 2. In the first embodiment, the drawer tray 41 can be taken out from a front side on which an opening 321 (described later) is provided.

As shown in FIGS. 1 to 3, the hood 3 is provided with a fixed hood 31 and a movable hood 32, and is configured such a manner that the fixed hood 31 is disposed on a rear side of the rectangular evacuation container 2, the rear side which is one end of the longitudinal direction, and is fixed with the evacuation container 2, and the movable hood 32 is disposed on a front side of the rectangular evacuation container 2, the front side which is the other end of the longitudinal direction, and has an overlapping portion 5 where the movable hood 32 overlaps with the fixed hood 31. In addition, the fixed hood 31 is connected with the movable hood 32 by a pair of connecting portions 33 at a portion of the overlapping portion 5 where the movable hood 32 overlaps with the fixed hood 31. The movable hood 32 is configured to be moved rotatably.

As shown in FIGS. 1 and 2, in the first embodiment, the fixed hood 31 covers approximately a half of the evacuation container 2 which is equivalent to the rear side of the evacuation container 2, and a top surface of the fixed hood 31 is formed as a nearly a circular arc surface which is curved from the one end of the front side toward the other end of the rear side. In addition, both side surfaces of the fixed hood 31 stand in nearly a vertical direction. Furthermore, the front side and the lower side of the fixed hood 31 is open. The movable hood 32 covers approximately a half of the evacuation container 2 which is equivalent to the front side of the evacuation container 2, and the external form is nearly a rectangular shape. That is, all of the front surface and both side surfaces located at the front side on the movable hood 32 stand in nearly a vertical direction, and the upper surface of the movable hood 32 extends in nearly a horizontal direction. In addition, the rear side and the lower side of the movable hood 32 are open.

As shown in FIGS. 1 and 2, the fixed hood 31 has a protrusion part 7 on an end of the lower side of the fixed hood 31, the protrusion part which protrudes externally in nearly a horizontal direction from the end. More specifically, a rear protrusion part 71 is formed on the end of the rear side on the top surface formed with a curvature of the fixed hood 31, and protrudes externally in the longitudinal direction in nearly a horizontal direction. In addition, a pair of fixed hood side protrusion parts 72 is formed on the lower ends of both side surfaces of the fixed hood 31, each of which protrudes externally in the width direction.

As shown in FIG. 2, a pair of stoppers 90 which protrudes upward toward the movable hood 32 is provided on the rear protrusion part 71. Thus, by providing the stoppers 90 on the rear protrusion part 71, a distance between the end of the rear side of the movable hood 32 and the rear protrusion part 71 is maintained when the movable hood 32 is in the open state. Accordingly, in a case where the movable hood 32 is moved from an open state to a closed state, the movable hood 32 can be easily moved from the open state to the closed state by inserting one's finger into the space. The height of the pair of stoppers 90 is preferably 5 to 35 millimeters, and more preferably 15 to 25 millimeters when inserting one's finger into the space thus formed.

One of the pair of the fixed hood side protrusion parts 72 is provided with a shovel holder 91 for holding a shovel (not shown) used when cleaning the animal litter box 1. The shovel holder 91 is provided proximal to an outer edge external to the width direction on the fixed hood side protrusion part 72 in such position so as not to be contacted with the movable hood 32 when the movable hood is moved rotatably.

Similar to the fixed hood 31, the movable hood 32 also has a protrusion part 7 on an end of the lower side of the movable hood 32 in the closed state, the protrusion part which protrudes externally in nearly a horizontal direction from the end. More specifically, as shown in FIG. 1, a front protrusion part 73 is formed on the lower end of the front side of the movable hood 32, and protrudes externally in the longitudinal direction in nearly a horizontal direction. In addition, a pair of the movable hood side protrusion parts 74 is formed on the lower ends of both side surfaces of the movable hood 32, each of which protrudes externally in each width direction. The front protrusion part 73 further protrudes in a longitudinal direction from the center part of the width direction, thus constituting a hood side handle 75 (see FIG. 1). With regard to the animal litter box 1 of the present embodiment, the movable hood 32 can be altered from the closed state to the open state using the hood side handle 75. An outer rim of the hood side handle 75 is formed to be a convexed shape which is curved in a longitudinal direction from a view of flat surface.

The movable hood 32 is provided with the opening 321 which links an inner space of the animal litter box 1 with an outer space at the front surface thereof, whereby an animal can go in and out the animal litter box 1 through the opening 321. The opening 321 may be formed as a square, rectangle, circle, ellipse, and the like, and is not limited to any specific shape as long as it is easy for an animal using the animal litter box 1 to go in and out. In the first embodiment, the opening 321 is formed to be a rectangular shape where a vertical direction is a long side of the rectangle.

As shown in FIG. 3, the fixed hood 31 and the movable hood 32 have the overlapping portion 5 where an end edge of the front side of the fixed hood 31 overlaps with an end edge of the rear side of the movable hood 32 when the movable hood 32 is in the closed state. In addition, the overlapping portion 5 is formed in such a manner that the movable hood 32 is located outside of the fixed hood 31. Furthermore, the pair of the connecting portions 33 is provided at end edges of the lower container in the overlapping portion 5, facing each other. Thus, the animal litter box 1 of the first embodiment is configured such that, in a case where the movable hood 32 is altered from the open state to the closed state, the movable hood 32 which is located outside of the fixed hood 31 can be moved rotatably with the pair of the connecting portions 33 operating as an axis. In addition, the pair of the connecting portions 33 may connect the movable hood 32 with the evacuation container 2 so that the movable hood 32 can be moved rotatably.

As shown in FIGS. 3 to 6, regarding the animal litter box 1 of the first embodiment, when the movable hood 32 is in the closed state, an end edge of at least the rear side of the movable hood 32 is proximal to the fixed hood 31 while maintaining a prescribed distance to the fixed hood 31. That is, an inner surface of an end edge of the rear side of the movable hood 32 lies in a vicinity of an outer surface of the fixed hood 31. In addition, as shown in FIG. 3, the top surface of the fixed hood 31 is configured as nearly a circular arc surface of which radius is from the connecting portion 33 to the end of the top surface. Therefore, in a case where the movable hood 32 is moved from the closed state to the open state, the movable hood 32 is configured to be moved outside of the fixed hood 31 with an end edge of at least the rear side of the movable hood 32 being proximal to the fixed hood 31 while maintaining a prescribed distance to the fixed hood 31 (see FIGS. 6 and 7). In addition, the movable hood 32 is formed to be approximately rectangular in the first embodiment. Therefore, in a case where the movable hood 32 is altered from the closed state to the open state, only a part in a vicinity of an end edge of the rear side on the upper surface of the movable hood 32 is moved rotatably with the part being proximal to the fixed hood 31. On the other hand, a rest other than the part in a vicinity of an end edge of the rear side on the upper surface of the movable hood 32 is moved rotatably with the rest being away from the fixed hood 31.

The fixed hood 31 and/or the movable hood 32 are provided with a convex restricting portion 6 which prevents the distance between an end edge of at least the rear side of the movable hood 32 and the fixed hood 31 from being less than a prescribed distance. In the first embodiment, as shown in FIGS. 4 to 6, the restricting portion 6 is composed of an inwardly protruding portion 61 which is formed on an inner surface of an end edge of the rear side on the upper surface of the movable hood 32.

Thus, by providing the convex restricting portion 6 to the fixed hood 31 and/or the movable hood 32, a distance L1 where the restricting portion 6 is provided between the movable hood 32 and the fixed hood 31 is less than a distance L2 where the restricting portion 6 is not provided between the movable hood 32 and the fixed hood 31. Accordingly, even in a case where the movable hood 32 or the fixed hood 31 is deformed such as by flexure, the movable hood 32 and the fixed hood 31 are contacted only at the restricting portion 6, thereby preventing those hoods from being closer to each other. Consequently, it can prevent the movable hood 32 from being stuck when it opens and closes, or it can prevent both hoods from being damaged by friction due to the movable hood 32 and the fixed hood 31 being in significant contact with each other.

The distance L2 where the restricting portion 6 is not provided between the inner surface of an end edge of at least the rear side of the movable hood 32 and the outer surface of the fixed hood 31 is preferably 1 to 10 millimeters, and more preferably 1 to 5 millimeters from the standpoint of sealing of the animal litter box 1 when the movable hood 32 is in the closed state. The distance L1 where the restricting portion 6 is provided between the movable hood 32 and the fixed hood 31 is preferably 0 to 3 millimeters, and more preferably 0 to 1 millimeter.

As shown in FIG. 2, in the first embodiment, a concave guiding groove 80 for guiding the moving of the protruding portion 61 when the movable hood 32 is moved from the closed state to the open state is provided on the outer upper surface of the fixed hood 31. The guiding groove 80, extends from the front side to the rear side, is formed at nearly a center part of the width direction on the top surface of the fixed hood 31, and is formed linearly along a curved shape of the top surface from the end of the front side to the end of the rear side.

It is preferred that width of the guiding groove 80 is formed broader than that of the protruding portion 61 from the standpoint of preventing slippage in the width direction when the movable hood 32 is opened or closed. More specifically, it is preferably 15 to 50 millimeters. The depth of the guiding groove 80 is preferably 5 to 20 millimeters, and more preferably 5 to 10 millimeters. In addition, from the standpoint described above, it is preferred that a distance L4 in a horizontal direction between the protruding portion 61 and the guiding groove 80 is less than a distance L3 in a horizontal direction between the movable hood 32 on the side surface of the hood 3 and the fixed hood 31 of the hood 3 (see FIG. 5).

As a constituent material for the evacuation container 2, the lower container 4, and the hood 3 which configures the animal litter box 1 of the first embodiment, any type of material which is normally used for an animal litter box may be used without any limitation. For example, synthetic resins such as polyethylene and polypropylene may be used.

According to the animal litter box 1 of the first embodiment with the abovementioned configuration, by providing the convex restricting portion 6 to the movable hood 32, even in a case where the movable hood 32 or the fixed hood 31 is deformed such as by flexure, the movable hood 32 and the fixed hood 31 will generally be contacted only at the restricting portion 6, thereby preventing those hoods from being closer to each other at other positions. Consequently, the present invention prevents the movable hood 32 from being stuck when it opens and closes. Therefore, the movable hood 32 can be opened and closed smoothly even though a distance between the movable hood 32 and a fixed hood 31 is reduced relative to prior art designs.

In addition, a concave guiding groove 80 for guiding the moving of the protruding portion 61 when the movable hood 32 is moved from the closed state to the open state is provided on the outer upper surface of the fixed hood 31. The guiding groove 80 extends from the front side to the rear side. Therefore, it can prevent from slippage in the width direction when the movable hood 32 is opened or closed, whereby the movable hood 32 can be opened and closed smoothly.

Next, the second embodiment and the third embodiment for an animal litter box of the present invention are described. Regarding the second embodiment and the third embodiment, differences from the first embodiment are mainly described, and the same reference numerals have been retained for similar parts so as to omit overlapping descriptions. Thus, unless otherwise noted, the second and third embodiments are similar to the first embodiment.

An animal litter box 1 of the second embodiment is mainly different from that of the first embodiment with regard to the number of restricting portions 6 with which are provided. Regarding the animal litter box 1 of the second embodiment, the restricting portion 6 is composed of one or more inwardly protruding portions 61 which are formed on an inner surface of an end edge of at least the rear side of the movable hood 32. More specifically, as shown in FIG. 8, three protruding portions 61 are provided on the upper surface and both side surfaces of the movable hood 32. In the second embodiment of the present invention, the fixed hood 31 is not provided with the guiding groove 80.

According to the animal litter box of the second embodiment, the protruding portions 61 which are the restricting portions 6 are provided to the upper surface and both the side surfaces of the movable hood 32 respectively. Therefore, it can prevent the movable hood 32 from slippage in a vertical direction and a width direction (a horizontal direction) without requiring the guiding groove 80 on the fixed hood 31, whereby the movable hood 32 can be opened and closed smoothly.

An animal litter box 1 of the third embodiment is different from the first embodiment in that the restricting portion 6 is provided on the fixed hood 31 and the guiding member 81 is provided on the movable hood 32. As shown in FIG. 9, regarding the animal litter box 1 of the third embodiment, the restricting portion 6 is composed of a convexity 62 which is formed on an outer upper surface of the fixed hood 31 and which extends from the front side to the rear side. The convexity 62 is formed at nearly a center part of the width direction on the top surface of the fixed hood 31, and formed linearly along a curved shape of the top surface from the end of the front side to the end of the rear side. In addition, on an inner surface of an end edge of at least the rear side of the movable hood 32, the guiding member 81 with a concavity which is hollow upward corresponding to a convexed shape of the convexity 62 is provided.

Therefore, the animal litter box 1 of the third embodiment can have the same effect as that of the first embodiment.

An animal litter box of the present invention is not limited to the abovementioned embodiments, and can be modified as appropriate without departing from the scope of the present invention. For example, in the first embodiment to the third embodiment, although the movable hood 32 is configured to be moved rotatably outside of the fixed hood 31, the movable hood 32 may alternatively be configured to be moved rotatably inside of the fixed hood. In this case, the restricting portion 6 can be provided either on an inner surface of the movable hood 32 or on an outer surface of the fixed hood 31.

In addition, in each of the embodiments from the first embodiment to the third embodiment, although the movable hood 32 is disposed on the front side of the evacuation container 2 and the fixed hood 31 is disposed on the rear side of the evacuation container 2, the movable hood 32 may be disposed on the rear side of the evacuation container 2 and the fixed hood 31 may be disposed on the front side of the evacuation container 2. In addition, in any one of the first through third embodiments, the top surface of the movable hood 32 may alternatively be configured as nearly a circular arc surface, which is similar to that of the fixed hood 31.

In the first embodiment and the second embodiment, as an alternative to forming protruding portion 61 on the inner surface of an end edge of the rear side on the upper surface of the movable hood 32, the protruding portion 61 may be formed so as to extend from an end of the rear side to an front side on the inner surface of an end edge of the rear side on the upper surface of the movable hood 32. In addition, in the second embodiment, although the protruding portion 61 which is the restricting portion 6 is provided on the movable hood 32, the protruding portion 61 may alternatively be provided on the fixed hood 31.

In addition, in the first embodiment to the third embodiment, although the evacuation container 2 is provided with the bottom part having a liquid permeable capability and the lower container 4 is disposed under the evacuation container 2, the evacuation container 4 may be without a liquid permeable capability or the lower container 4 may not be disposed under the evacuation container 2.

An animal litter box of the present invention may be used as a litter box for an animal kept as a pet such as cats, dogs, rabbits, and the like. Specifically, an animal litter box of the present invention can be preferably used as a litter box for a cat kept indoors. 

1. An animal litter box comprising: an evacuation container of which an upper surface has an opening; and a hood disposed above the evacuation container so as to cover the opening, the hood having a fixed hood disposed on one end of the evacuation container, a movable hood disposed on the other end of the evacuation container, and a pair of connecting portions which connect the movable hood to be moved rotatably, wherein the movable hood is configured to be moved rotatably outside the fixed hood in the state that an end edge on at least the one end of the movable hood is proximal to the fixed hood with maintaining a prescribed distance, and includes a convex restricting portion which prevents a distance between an end edge on at least the one end of the movable hood and the fixed hood from being less than the prescribed distance, wherein the convex restricting portion is composed of an inwardly protruding portion which is formed on an inner surface of the end edge on at least the one end of the movable hood; and wherein the fixed hood includes a concave guide groove which extends from one side edge to another side edge of the fixed hood, on an outer upper surface thereof, to guide the moving of the protruding portion when the movable hood is moved from a closed state to an open state.
 2. An animal litter box comprising: an evacuation container of which an upper surface has an opening; and a hood disposed above the evacuation container so as to cover the opening, the hood having a fixed hood disposed on one end of the evacuation container, a movable hood disposed on the other end of the evacuation container, and a pair of connecting portions which connect the movable hood to be moved rotatably, wherein the movable hood is configured to be moved rotatably outside the fixed hood in the state that an end edge on at least the one end of the movable hood is proximal to the fixed hood with maintaining a prescribed distance, and includes a convex restricting portion which prevents a distance between an end edge on at least the one end of the movable hood and the fixed hood from being less than the prescribed distance, the convex restriction portion is composed of one or more inwardly protruding portions which are formed on an inner surface at an end edge on at least the one end of the movable hood, and wherein the fixed hood includes a concave guide groove which extends from one side edge to another side edge of the fixed hood, to guide the convex restricting portion.
 3. An animal litter box comprising: an evacuation container of which an upper surface has an opening; and a hood disposed above the evacuation container so as to cover the opening, the hood having a fixed hood disposed on one end of the evacuation container, a movable hood disposed on the other end of the evacuation container, and a pair of connecting portions which connect the movable hood to be moved rotatably, wherein the movable hood is configured to be moved rotatably outside the fixed hood in the state that an end edge on at least the one end of the movable hood is proximal to the fixed hood with maintaining a prescribed distance, wherein the fixed hood includes: a convex restricting portion which prevents a distance between an end edge on at least the one end of the movable hood and the fixed hood from being less than the prescribed distance, the convex restricting portion being composed of a convexity which is formed on an outer surface of the fixed hood; and wherein the movable hood includes a concave guide groove which extends from one side edge to another side edge of the movable hood, to guide the convex restricting portion, the concave guide groove has a concavity which is hollow upward on an inner surface at the end edge on at least the one end of the movable hood, corresponding to a convex shape of the convexity of the convex restricting portion. 